Sting function for API

[stranger123]

Hi,

When pass a string between VB and API, what is the difference by use String(255, chr(32)) and String(255, chr(0))?

Thank you in advance.

 

[CassandraR]

Big difference.

String(255, Chr(0)) is a string of 255 null (ASCII zero) characters. The null characters are the usual end of string marker. So, a string of 255 null characters is unlikely to cause string overrun.

String(255, Chr(32)) is a string of 255 spaces. It doesn't necessarily have an end of string marker, as expected by a lot API calls. To be safe, one should pass a buffer that is null terminated.


Cassie
PIII-500Mhz-128MB
Win98SE-VB6SP5

 

[stranger123]

Thank you.
I have just tested it is not working by use
String(254,chr(32)) & chr(0)

 

[BobRodes]

If you post your code (stripping out the irrelevant parts), we might be able to help. Normally the APIs use null terminated strings.

 

[strongm]

>To be safe, one should pass a buffer that is null terminated.

Well, that was certainly the case in older versions of VB. However, VB6 uses BSTRs, which are already null-terminated